what i do is drag my videos to the "videos" tab on iTunes.. Plug in my iPhone click on videos tab or movies click on sync all. something pops up saying you change settings click yes then it should work.
I use the "Add File to Library" or "Add Folder to Library" depending if its just one or many. It will know if its a music song or a video. Also remember that if you are using video's you converted then they show up as movies not as video's.
I used HANDBRAKE, and easily converted the movie. I see it in the Video area of iTunes, but it, and others won't sync. Some of them sync, but this one won't. I saved it as MP4, and can view it through iTunes on my desktop. I tried the drag and drop, and import, but the tab for VIDEOS, only shows, that I have none rented, and TV shows, but no tab for MOVIES, on top of SYNC screen. I see under LIBRARY on iTUNES.. a MOVIE area, and my movie is in there. Can someone, help me on this please? I have the latest version of both. THANKS!